As long as you are health conscious and managing any conditions well, you'll get the best possible rates regardless of what outdated measurement practices say. (healthiq.com)
A favorite target are the adjustments that occur as these observational records are gradually being vetted and improved by adding new data and eliminating artifacts that arise e.g. from changing measurement practices or the urban heat island effect. (realclimate.org)
There are very substantial known changes in SST measurement practices during WWII, which are hard to correct for completely. (skepticalscience.com)